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SEAD 520 > Impact Assessment > Flashcards

Impact Assessment Flashcards

1
Q

What are the elements of impact assessment?

A
  1. Selection
  2. Classification
  3. Characterization
  4. Normalization
  5. Grouping or weighting

(First three are mandatory)

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2
Q

Why is characterization needed?

A
  • Taking a decision on inventory requires too many implicit hypothesis. We need to be transparent, justify the choices and base them on scientific criteria
  • It allows for a lower number of criteria in decision making
  • Assess the magnitude of potential impacts of a product system on the environment though its life cycle
  • Makes the inventory interpretable
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3
Q

Why does the LCIA only represent potential impact through the assessed impacts?

A

No real impacts, exceeding standards, or risks due to:

  • The relative expression of impacts in relation to a reference (i.e., fun unit)
  • Integration of environmental data in space and time
  • Inherent uncertainty in impact modeling
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4
Q

What is the definition of classification?

A

Classification allows to attribute inventory results to impact categories
(i.e., match result to impact)

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5
Q

What is an impact pathway?

A
  • A set of environmental mechanisms

- It allows to give the “paths” leading to all impacts included in a impact category

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6
Q

How can impact pathways be illustrated

A
  1. In parallel

2. In Series (directly or indirectly)

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7
Q

What is the definition of characterization?

A

Calculation which converts the inventory value in a metric with common unit for each impact category.

  1. Contributions of all inputs and outputs to each impact category are assessed
  2. Contributions to the same impact category are added
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8
Q

What is the definition of an impact category?

A

Class representing environmental issues of concerns to which LCI results may be assigned

(Ex. Climate change, acidification)

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9
Q

What is the definition of a category indicator?

A

Quantifiable representation of an impact category

Ex. Infrared radiative forcing, proton release

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10
Q

What is the definition of a characterization model?

A

Mathematical model of the impact of elementary flows wrt a particular category indicator. Provides a basis for the characterization factor.

(Ex. model for climate change, model for acidifying substances)

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11
Q

What is the definition of the characterization factor?

A

A factor derived from a characterization model which is applied to convert the assigned LCI results to the common unit of the category indicator.

(Ex. Global warming potential (GWP), Acidification potential (AP))

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12
Q

What is the definition of the midpoint impact category indicator?

A

Midpoint; low order effect

Can be located at any intermediate position between the LCI results and the damage category in the cause-effect chain

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13
Q

What is another term for the damage category indicator?

A

Endpoint; higher order effect

Quantified representation of a change in environmental quality

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14
Q

How does the uncertainty vary between the interpretation, models, and impact results along the LCI, midpoint, and endpoint

A
  • Commonly accepted that as one moves from midpoint to endpoint LCIA modelling,
    the relevance increases, but the uncertainty also increases
  • Also commonly accepted that indicators should be chosen in such a fashion that “total
    uncertainty” is minimized
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15
Q

What is the formula for the characterization sumproduct (midpoint indicator or impact score)?

A

Sj = sumi ( CFji *Mi)

S = Impact score for category j (ex. kg Co2 eq) 
CF = Characterization factor of elementary flow i for impact category j (ex. in kg Co2 eq / kg of i) 
Mi = elementary flow related to the functional unit (ex. kg of i)
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16
Q

What is the overall framework for the impact factor?

A

Impact = Emission x CF

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17
Q

What factors can the characterization factor be broken into?

A 
Fate factor (FF) 
Exposure factor (XF) 
Effect factor (EF)
18
Q

What is the indicator unit for each damage category?

A

Human health (HH) –> DALY (years of life in good health lost, taking into account premature mortality and morbidity)

Ecosystem quality (EQ) –> PDF m^2 yr (fraction of species disappeared over a certain area for a certain time)

Resources (R) –> $

19
Q

What is the definition of normalization?

A

Calculation of the magnitude of category indicator results to reference information

Reference information: area, person, product

20
Q

Why is normalization done?

A
  • To check for inconsistencies
  • To provide and communicate information on the relative significance of the indicator results
  • Preparing for additional procedures
21
Q

What should you be cautious of during normalization?

A
  • Normalized results only express the magnitude of an impact in relation to the impact of the normalization reference
  • Gives no indication of the relative importance of this impact vs others
  • High risk of misinterpretation of normalized results, tendency to read too deep into it
22
Q

What is the definition of weighting?

A

Converting and possibly aggregating indicator results across impact categories using numerical factors

Provides a single score

23
Q

What are the weighing principles?

A
  1. Social assessment (i.e., “Willingness to pay” for a healthy life or clean environment )
  2. Cost of prevention of remediation (e.g., $ or MJ)
  3. Experts or stakeholders panel
  4. “Distance to target” (e.g. legislative objectives)
24
Q

What are the issues with weighting?

A
  • There is no scientific basis to aggregate results into a single score (social value choices)
  • Weighting and aggregation not permitted for LCA used to support public comparative assertion
  • If weighting is to be done, much easier to weight damages of endpoints than midpoints
25
Q

What are the different value choice management visions?

A
  1. Individualist (I)
  2. Hierarchist (H)
  3. Egalitarian (E)

Social science based perspectives of grouping

26
Q

Describe the individualist value choice management vision?

A

Time perspective: Short-term
Problem Manageability: Technology can avoid many problems
Required level of evidence: Only proven effects

27
Q

Describe the hierachist value choice management vision?

A

Time perspective: Balance between short term and long term
Manageability: Proper policy can avoid many problems
Required level of evidence: Inclusion based on consensus

28
Q

Describe the egalitarian value choice management vision?

A

Time perspective: very long term
Manageability: Problems can lead to catastrophe
Required level of evidence: All possible effects

29
Q

What are the specific midpoint impact categories (add slides to summarize them):

A
  1. Climate change
  2. Water use
  3. Ozone depletion
  4. Eutrophication
  5. Acidification
  6. Particulate matter
  7. Land use
  8. Toxicity
30
Q

What are the available LCIA methods discussed in class?

A

Impact World+
ReCiPe
LUCAS

31
Q

Why and how do methods of CF differ?

A
  1. Difference in characterization method:
    - Value choices / hypotheses
    - Choice of impact pathway used
    - Algorithms
  2. Difference in parameterization / regionalization
  3. Difference in temporal boundary
32
Q

What are the key points for a good LCIA?

A
  • Use more than one method to test robustness of conclusions, there is not one generally accepted method
  • Characterization models should minimally take into consideration the fate and effect of emitted substances
  • Very good way to do a sensitivity analysis
33
Q

What are the critics on use of LCA?

A
  • Lots of confusion on which method to use

- Potentially, results differ based on the method used

34
Q

Describe the climate change impact category

A

Problems: specific impacts on climate
Env Mech: Greenhouse effect (connected to HH and E)
Emissions: Carbon dioxide, methane, nitrous oxide
Char Models: IMPACT 2002+ (refrains from endpoint modeling)

35
Q

Describe the ozone depletion/formation impact category?

A

Depletion –> Stratospheric
Formation –> Tropospheric

Problem: ozone hole leads to increased UV radiation
Env Mech: Damage to HH and E
Emissions: CH4 N2O and halogenated substances
Char Models: LIME (only one that considers E)

36
Q

Describe the Acidification midpoint category?

A

Problem: lower health of forests, and lakes
Env Mech: leads to a fall in systems acid neutralizing capacity, reduction of pH in receiving area
Emissions: Co2, NO2, NH3, So2
Char Models: No specific model given

37
Q

Describe the Eutrophication midpoint category?

A

Problem: enrichment of aquatic environment with salts to increased biomass production which results in degradation of water quality (swamp)
Env Mech: Emission of N or P, growth of biomass increases, sunlight no longer reaches lower water layers, creates temperature gradient, this educes the transport of fresh oxygen-rich surface water to deeper layers
Emissions: fertilizers, manure, runoffs
Char Models: Most models associate with E using PDF or Net Primary Productivity (NPP) [FATE or EFFECT]

38
Q

Describe the human toxicity/ecotoxicity midpoints?

A

Human toxicity –> HH

Ecotoxicity –> E

39
Q

Describe the particulate matter formation midpoint?

A

Mass emitted to air –> time-integrated mass in air –> mass inhaled –> disease incidence –> HH

40
Q

Describe the land use and water use midpoints?

A

Water use –> HH and E

Land use –> HH, E, and R

SEAD 520 (11 decks)

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